Simpson Grading System Research Articles

The Role of Simpson Grading System in Spinal Meningioma Surgery: Institutional Case Series, Systematic Review and Meta-Analysis

Background: Although its validity has recently been questioned since its introduction, the Simpson grade has remained one of the most relevant factors in estimating the recurrence risk of intracranial meningiomas. This study aims to assess its role in spinal meningiomas through a retrospective analysis of a mono-institutional surgical series and literature meta-analysis. Methods: We conducted a systematic review and meta-analysis of the literature from 1980 to 2023, complemented by a mono-institutional series of 74 patients treated at “Santa Maria delle Grazie” hospital. Demographic, clinical, neuroradiological, pathological, surgical, and outcome data of case series were analyzed. For the meta-analysis, studies were selected based on predefined inclusion criteria, and a fixed-effects model was used to synthesize data due to assumed homogeneity among included studies. Statistical analyses included odds ratios (OR) for recurrence risk and assessment of publication bias using Peter’s test. Results: Mono-institutional sample included 74 patients, most of whom were women (85%) with a median age of 61.9 years. The thoracic spine was the most common tumor location (81%). Recurrences occurred in patients with Simpson grade II and III resections. The meta-analysis involved 2142 patients from 25 studies and revealed a significantly higher recurrence rate for Simpson grades III–V compared to grades I–II (OR 0.10; CI95 0.06–0.16). Additionally, Simpson grade II had a higher recurrence risk than grade I (OR 0.42; CI95 0.20–0.90). Conclusions: The Simpson grading remains a valid predictor of recurrence also for spinal meningiomas. Our findings revealed a significant increase in recurrence rate with higher Simpson grades. These results support the need to strive for Simpson grade I resection when feasible.

The Impact of Molecular and Genetic Analysis on the Treatment of Patients with Atypical Meningiomas.

Meningiomas represent approximately 40% of all primary tumors of the central nervous system (CNS) and, based on the latest World Health Organization (WHO) guidelines, are classified into three grades and fifteen subtypes. The optimal treatment comprises gross total tumor resection. The WHO grade and the extent of tumor resection assessed by the Simpson grading system are the most important predictors of recurrence. Atypical meningiomas, a grade 2 meningioma, which represent almost a fifth of all meningiomas, have a recurrence rate of around 50%. Currently, different histopathologic, cytogenetic, and molecular genetic alterations have been associated with different meningioma phenotypes; however, the data are insufficient to enable the development of specific treatment plans. The optimal treatment, in terms of adjuvant radiotherapy and postoperative systemic therapy in atypical meningiomas, remains controversial, with inconclusive evidence in the literature and existing studies. We review the recent literature to identify studies investigating relevant atypical meningioma biomarkers and their clinical application and effects on treatment options.

A tribute to the late Professor Donald Simpson, Australian neurosurgeon and namesake of the Simpson grading system for meningioma extent of resection.

Donald Simpson (1927-2018) was a neurosurgeon from Adelaide, Australia, who is often cited for the 1957 publication he wrote as a trainee on the relationship between extent of resection and outcomes for meningiomas. That paper summarized a series of over 300 patients operated on in England by well-known neurosurgeons Sir Hugh Cairns and Joseph Buford Pennybacker. Simpson was also known later in his career, when he was at the University of Adelaide in South Australia, for his contributions to the areas of hydrocephalus, spina bifida, craniofacial anomalies, head injury, brain abscesses, and neurosurgical history, and he published extensively on these topics. In addition to his work in clinical neurosurgery, Simpson made humanitarian contributions studying kuru in New Guinea and aiding refugees during the Vietnam War. Simpson was an active member and leader of many Australian surgical organizations and was an officer of the Order of Australia. Donald Simpson's legacy as an adult and pediatric neurosurgeon, an academician, a leader, and a humanitarian is extensive and will prove long lasting. Professor Simpson's life serves as an example from which all neurosurgeons may learn.

Value of KI-67/MIB-1 labeling index and simpson grading system to predict the recurrence of who grade I intracranial meningiomas compared to who grade II

Simpson grading of resection has been used as a predictor of intracranial meningioma (IM) recurrence. Histopathological findings, like the Ki-67/MIB-1 labeling index, may be useful in the assessment risk of recurrence. Our objective was to analyze the predictive value of meningioma recurrence using both parameters. We retrospectively studied 322 consecutive patients with histopathological diagnosis of IM WHO grade I and 43 patients with IM WHO grade II in a 13-year period. Multivariate survival analysis was performed. In the WHO grade I IM group, recurrence was observed in 28 patients (8.69%). The Cox regression model for WHO grade I IM, provided a significative hazard ratio (HR) for Ki-67/MIB-1 index ≥3 (HR = 36.35, p < 0.001) and Simpson’s grading resection, grade II (HR = 2.03, p = 0.045), grade III (HR = 3.41, p = 0.034) and grade IV (HR = 19.75, p ≥ 0.001). In the WHO grade II IM group, recurrence was observed in 10 patients (23.25%). The Cox regression model for WHO grade II IM, provided a significative hazard ratio (HR) for Ki-67/MIB-1 index ≥3% (HR = 1.66, p < 0.001) and Simpson’s grading resection grade III (HR = 3.96, p = 0.027). The Kaplan–Meier survival curve showed a similar distribution of survival between WHO grade I IM with Ki-67/MIB-1 ≥3% and WHO grade II IM. In WHO grade I meningiomas, the Ki-67/MIB-1 index and Simpson grading were both independent predictors of recurrence. A similar management protocol should be advisable for WHO grade I with Ki-67/MIB-1 ≥3% and WHO grade II meningiomas.

Surgical Management of Middle Cranial Fossa Meningiomas: Experience of 35 Cases

Abstract Background: Meningiomas are the most common tumors of the middle cranial fossa. Different surgical approaches have been described for excision of these tumors. Common approaches are the pterional, subtemporal, and the subfrontal approaches. These tumors are challenging in their management due to the variability of their surgical routes, and due to their close proximity to the cavernous sinus, carotids, optics, and other cranial nerves. Aim of Study: Discussing our experience in surgical excision of middle cranial fossa meningiomas, discussing different surgical routes and incidence of morbidities and mortalities. Patients and Methods: This is a retrospective observational study conducted on the data of 35 cases with middle cranial fossa meningiomas between January 2016 and July 2017. We included data of cases with outer (Pterional), middle and inner sphenoid wing (clinoidal), suprasellar, and cavernous sinus meningiomas. The Simpson grading system was utilized for assessment of the extent of tumor excisions; while the Karnof-sky performance scale as well as the comparison between the pre and the postoperative clinical examination was utilized for assessment of the functional outcomes. Results: 6 convexity meningiomas, 12 suprasellar menin-giomas, and 17 middle and inner sphenoid wing meningiomas (clinoidal) including cavernous sinus extension were included in the study. Simpson grade 1 excision was achieved in 34%, grade 2 in 46%, grade 3 and 4 in 20%. Visual functions improved in 57% of cases. The most common complication was cranial nerve affection. We didn't detect any cases with tumor recurrences. Conclusion: Middle cranial fossa meningiomas are chal-lenging cases that are becoming possible for gross total surgical excision with minimal complications. Cranial nerves palsies are the most common morbidities specially the optic nerve and the cranial nerves in the region of the cavernous sinus. The pterional approach is considered to be the key approach for most types.

Microsurgical treatment of large and giant parasagittal meningioma invading the superior sagittal sinus

Objective To investigate the method and effect of microsurgical removal of large and giant parasagittal meningioma invading the superior sagittal sinus. Methods The clinical data of 154 cases with large and giant parasagittal meningioma invading the superior sagittal sinus admitted to Department of Neurosurgery, Peking University Third Hospital from May 2009 to May 2019 were retrospectively analyzed. The diameter of the tumors ranged from 4 cm to 8 cm, with an average of 5.5±1.2 cm. Microsurgical resection was carried out along the midline and longitudinal fissure with a horse-shoe shaped skin incision turning to the temporal side. The degree of resection was evaluated by Simpson grading system. The results of clinical follow-up were evaluated by Karnofsky performance score (KPS), and the tumor recurrence was evaluated by imaging follow-up. Results Among the 154 cases, Simpson grade Ⅰ resection was achieved in 112 (72.7%) and grade Ⅱ resection in 42 cases (27.3%). All of them were proved to be meningiomas (World Health Organization grade Ⅰ). The operation time ranged from 30 minutes to 210 minutes (median: 60 minutes), and the length of stay ranged from 5 days to 10 days with an average of 7.2±1.1 days. There was no infection, cerebrospinal fluid leakage, death or permanent aggravation of neurological dysfunction. The patients were followed up for 3 months to 123 months, with an average of 63.5±0.7 months. The KPS score ranged from 80 points to 100 points, with an average of 93.6±0.3 points. Tumor recurrence occurred in 14 patients (9.1%), including 7 in Simpson Ⅰ resection group and 7 in Simpson Ⅱ resection group. There was significant difference in recurrence rate between the 2 groups (χ2=4.01, P<0.05). Conclusion Simpson grade Ⅰ microsurgical resection can be pursued for large and giant parasagittal meningioma invading the superior sagittal sinus which helps minimize the recurrence rate. Key words: Meningioma; Microsurgery; Treatment outcome; Sagittal sinus; Large and giant

Tumor recurrence in parasagittal and falcine atypical meningiomas invading the superior sagittal sinus.

Objective: Parasagittal and falcine meningiomas are still a challenge in terms of surgical resection. Although maximal safe resection is the main therapeutic approach, numerous postoperative complications can still occur depending on the locations of these tumors. Moreover, previous studies have reported that parasagittal meningiomas have a higher recurrence rate than meningiomas with other locations. Patients, Materials and Methods: We retrospectively reviewed 21 patients with parasagittal and falcine atypical meningiomas [World Health Organization (WHO) grade II], nine of whom had their superior sagittal sinus (SSS) invaded by the tumor. We reviewed the demographic information, operative notes, pathological reports, and clinical and imagistic follow-up reports of each patient over a 5-year time span. Results: All the patients were surgically treated, and the tumor removal was grade II according to Simpson’s grading system in 47.6% and grade III in 19% of the cases. The SSS was invaded in 42.9% of the patients. No immediate mortality or morbidity was revealed by our study. Tumor recurrence/progression documented on postoperative imaging amounted to 14.3% and 19%, 12 and 24 months after surgery, respectively. Furthermore, 36, 48 and 60 months after the surgery, the recurrence rate remained the same, namely in 9.5% of the cases. The recurrence was higher in patients with SSS invasion than in patients with no SSS invasion. The tumor recurrence was slightly more predominant in women, i.e., 6% higher than in the male group. Conclusions: In our group of patients with parasagittal and falcine meningiomas, we report a 47.6% Simpson II resection rate and 19% Simpson III resection rate associated with a very low complication rate and no immediately postoperative morbidity and mortality, compared to more aggressive techniques. The recurrence of parasagittal meningiomas predominated after grade III and IV Simpson resection and dural sinus invasion was a negative predictive factor for recurrence. Therefore, the surgery of parasagittal and falcine meningiomas is beneficial, both for tumor control, but also for improving neurological outcome. Aggressive meningioma resection should be balanced with the increased neurosurgical risk.

Is the Simpson Grading System Applicable to Estimate the Risk of Tumor Progression After Microsurgery for Recurrent Intracranial Meningioma?

We analyzed the applicability of the Simpson grading system to estimate the risk of tumor recurrence after microsurgery for recurrent meningiomas. Correlations between the Simpson grade and the extent of resection (EOR) (gross total resection [Simpson grade I and II] vs. subtotal resection [Simpson grade ≥III]) with tumor relapse after microsurgery for meningioma recurrence were investigated compared with the findings in primary diagnosed tumors. Location-specific differences were further elucidated in subgroup analyses. A total of 829 individuals (88% in group A) with primary diagnosed meningioma and 109 patients with first postoperative recurrence (12% in group B) who underwent surgery were included. In group A, both Simpson grade (P= 0.003) and EOR (P < 0.001) correlated strongly with recurrence. In group B, Simpson grade correlated with tumor location (P= 0.030), and the risk of subtotal resection was greater in the posterior fossa (odds ratio, 5.26; P= 0.018) and skull base (odds ratio, 6.16; P= 0.002) meningiomas. Older age at tumor relapse (hazard ratio [HR], 1.05; P= 0.001), male sex (HR, 2.19; P= 0.02), and grade 2/3 histologic findings (HR, 2.18; P= 0.02). However, neither the Simpson grade nor dichotomized EOR correlated with further tumor recurrence. The frequency of postoperative complications was similar in both groups. Surgery for recurrent meningiomas is not generally associated with an increased risk of postoperative complications compared with resection of primary diagnosed tumors. However, the Simpson grade and EOR in recurrent meningiomas correlated poorly with further tumor relapse. The lower prognostic value of the tumor remnants left behind during microsurgery for recurrent meningiomas should be considered when operating on lesions that can be surgically challenging.

The Relevance of Simpson Grade Resections in Modern Neurosurgical Treatment of World Health Organization Grade I, II, and III Meningiomas.

The Simpson grading system has played an important role in surgical resections of meningiomas. The aim of this study was to determine if this grading system predicts meningioma recurrence in a modern cohort of patients with tumors of all World Health Organization grades. Adult patients who underwent primary, nonbiopsy resection of a meningioma at a tertiary care institution between 2007 and 2015 were retrospectively reviewed. Stepwise multivariate proportional hazard analyses were used to identify associations with recurrence after resection. Log-rank analyses were used to compare Kaplan-Meier plots for time to recurrence between each Simpson grade. Of 572 patients who met inclusion criteria, 72 (12.6%) presented with recurrence. Factors associated withrecurrence after gross total resection (Simpson grades I-III) were non-World Health Organization grade I (hazard ratio [HR] [95% confidence interval (CI)] 6.215 [2.864-12.419], P < 0.0001) and preoperative neurologic deficits (HR [95% CI] 2.862 [1.512-5.499], P= 0.001). Factors associated with recurrence after subtotal resections (Simpson IV) were African American race (HR [95% CI] 2.776 [1.232-5.890], P= 0.02) and parafalcine location (HR [95% CI] 3.956 [1.624-8.775], P= 0.004). Simpson grade was not an independent risk factor for recurrence. Identification and consideration of factors associated with recurrence after gross total or subtotal resections may help guide treatment strategies for patients with meningiomas.

Relevance of Simpson's grading system for resections in WHO grade I meningiomas

ObjectThe aim of this study is to assess if the recurrence rates and recurrence/progression-free survivals (RFS) are different after Simpson's grades I, II, III and IV resections in World Health Organisation (WHO) grade I meningiomas. Material and methodsA retrospective review was conducted on the data of patients who underwent surgical treatment of WHO grade I meningiomas located in convexity, falx/parasagittal, and skull base (anterior/media/posterior) between June 1991 and December 2011. In Simpson's grade IV resections, surgical treatment was supplemented with radiotherapy/radiosurgery on the tumour remains. A comparison was made on the recurrence rates and RFSs between Simpson's grades I, II, III, and IV resections, both overall and in tumour subsets according to their location. ResultsA total of 208 meningiomas were included in this study. There were no significant differences in recurrence rates and RFSs between Simpson's grades I, II, III, and IV. No significant differences were noted between the different degrees of Simpson in any of the location groups. In convexity meningiomas, the recurrence rates were 7% and 33% in Simpson's grades I and III resections, respectively (p=.131). ConclusionsIt has been shown that the rates of tumour control in meningiomas are not related to Simpson grades. In falx/parasagittal and skull base meningiomas, more aggressive attempts of tumour resection must be balanced against the risks of damaging critical neurovascular structures. In convexity meningiomas, a Simpson's grade I resection should be attempted first.

Relevance of Simpson's grading system for resections in WHO grade I meningiomas

The aim of this study is to assess if the recurrence rates and recurrence/progression-free survivals (RFS) are different after Simpson's grades I, II, III and IV resections in World Health Organization (WHO) grade I meningiomas. A retrospective review was conducted on the data of patients who underwent surgical treatment of WHO grade I meningiomas located in convexity, falx/parasagittal, and skull base (anterior/media/posterior) between June 1991 and December 2011. In Simpson's grade IV resections, surgical treatment was supplemented with radiotherapy/radiosurgery on the tumour remains. A comparison was made on the recurrence rates and RFSs between Simpson's grades I, II, III, and IV resections, both overall and in tumour subsets according to their location. A total of 208 meningiomas were included in this study. There were no significant differences in recurrence rates and RFSs between Simpson's grades I, II, III, and IV. No significant differences were noted between the different degrees of Simpson in any of the location groups. In convexity meningiomas, the recurrence rates were 7% and 33% in Simpson's grades I and III resections, respectively (P=.131). It has been shown that the rates of tumour control in meningiomas are not related to Simpson grades. In falx/parasagittal and skull base meningiomas, more aggressive attempts of tumour resection must be balanced against the risks of damaging critical neurovascular structures. In convexity meningiomas, a Simpson's grade I resection should be attempted first.

Re-Evaluating Simpson Grade I, II, and III Resections in Neurosurgical Treatment of World Health Organization Grade I Meningiomas

Since 1957, the Simpson grading system has been considered a predictive system for meningioma recurrence. However, since then, surgical equipment and neurosurgical technique have developed extensively, so this grading system should be re-evaluated. This study aims to assess if the recurrence rate and recurrence-free survival (RFS) are different after Simpson grade I, II, and III resections in World Health Organization (WHO) grade I meningiomas. We retrospectively reviewed the data of patients who underwent surgical treatment of WHO grade I meningiomas located in the convexity (group 1), falx/parasagittal (group 2), skull base, and tentorium (group 3) between June 1991 and December 2011. We compared the recurrence rates and RFSs between Simpson grade I, II, and III resections in both overall cases and tumor subsets according to their localization. A total of 224 meningiomas were included in this study. There were no significant differences in recurrence rates and RFSs between Simpson grades I, II, and III. In each of the location groups, no significant differences were noted between the different degrees of Simpson. We have shown that complete resection of WHO grade I meningiomas achieves excellent tumor control, regardless of Simpson grades. More aggressive attempts at tumor resection (ie, Simpson grade I) must be balanced against the risks of removing dura or damaging critical neurovascular structures.

A study of prognostic factors in 45 cases of atypical meningioma.

Atypical meningioma differs from Grade I meningioma in terms of high recurrence rate and short life expectancy. We evaluated the clinical course of atypical meningioma and investigated prognostic factors affecting its outcomes. We reviewed 45 patients with atypical meningioma who underwent surgical intervention between January 2000 and December 2013. The mean age of the patients and mean follow-up period was 58.7years and 81.0months, respectively. Analyses included factors such as patient age, gender, location and size of tumor, extent of surgical resection (Simpson Grading System), and MIB-1 labeling index (LI). Univariate analysis was used to detect prognostic factors associated with recurrence and survival. The 5-year recurrence-free rate for all 45 patients was 58.4%; 5- and 10-year survival rates were 83.2% and 79.9%, respectively. In univariate analyses, age >60years, and MIB-1 LI correlated with disease recurrence, whereas age >60years, subtotal surgical resection, MIB-1 LI, and indication for radiotherapy correlated with death. MIB-1 LI levels higher than 12.8% and 19.7% predicted recurrence and death, respectively. In our cohort, 26 patients received postoperative radiotherapy including conventional radiation (n = 21) or gamma knife radiosurgery (n = 5). Postoperative radiotherapy did not decrease recurrence rates in our cohort (p = 0.63). Six and two patients who died during the study period underwent conventional radiation and radiosurgery, respectively. Age, male gender, extent of surgical resection, and higher MIB-1 LI influenced the outcome of atypical meningioma. In our cohort, postoperative radiotherapy failed to provide long-term tumor control. Following incomplete surgical resection of atypical meningioma in elderly patients, adjuvant postoperative radiotherapy may not be an ideal treatment option, particularly when MIB-1 LI is higher than 19.7%.

Outcome of resection of WHO Grade II meningioma and correlation of pathological and radiological predictive factors for recurrence

This study investigated whether extent of surgical resection (Simpson and Shinshu grade) along with pathological and radiological factors influence the tumor control and recurrence-free survival (RFS) of patients with World Health Organization (WHO) grade II meningiomas. The clinical, radiological and surgical notes on the 59 patients with WHO grade II meningioma managed at our institution over 20years were retrospectively reviewed. In this study, median survival time was 41months. The overall recurrence rate in Simpson grades I and II resection was 31%. In grades III and IV, the overall recurrence rate was 73%, and this high recurrence rate in these groups was confined within 5years. In Cox regression analysis, combined data of grades (I and II)/complete resection showed a significant difference in RFS compared to grades (III and IV)/subtotal resection (p=0.0001). A similar trend of RFS (p=0.0001) was observed with the Shinshu grading system of resection. In addition, a Ki-67% marker for proliferation less than 15% (p=0.029), absence of certain radiological features including heterogeneous enhancement, cyst formation and peritumoral edema (p=0.006), and repeat surgery for recurrent meningioma was associated with better survival (p=0.014). However, radiosurgery did not have a beneficial role in the treatment of recurrence of atypical meningioma. The Simpson grading system is the primary predictor of recurrence of WHO grade II meningioma after resection. In addition, certain pathological and radiological features need to be considered as possible factors of recurrence after resection. Lastly, depending on the likely risks and surgical morbidity, repeat surgical resection should be performed for recurrent atypical meningioma.

Relevance of Simpson grading system and recurrence-free survival after surgery for World Health Organization Grade I meningioma.

OBJECTIVE The clinical significance of the Simpson system for grading the extent of meningioma resection and its role as a predictor of the recurrence of World Health Organization (WHO) Grade I meningiomas have been questioned in the past, echoing changes in meningioma surgery over the years. The authors reviewed their experience in resecting WHO Grade I meningiomas and assessed the association between extent of resection, as evaluated using the Simpson classification, and recurrence-free survival (RFS) of patients after meningioma surgery. METHODS Clinical and radiological information for patients with WHO Grade I meningiomas who had undergone resective surgery over the past 20 years was retrospectively reviewed. Simpson and Shinshu grading scales were used to evaluate the extent of resection. Statistical analysis was conducted using Kaplan-Meier curves and Cox proportional-hazards regression. RESULTS Four hundred fifty-eight patients were eligible for analysis. Overall tumor recurrence rates for Simpson resection Grades I, II, III, and IV were 5%, 22%, 31%, and 35%, respectively. After Cox regression analysis, Simpson Grade I (extensive resection) was revealed as a significant predictor of RFS (p = 0.003). Patients undergoing Simpson Grade I and II resections showed significant improvement in RFS compared with patients undergoing Grade III and IV resections (p = 0.005). Extent of resection had a significant effect on recurrence rates for both skull base (p = 0.047) and convexity (p = 0.012) meningiomas. Female sex and a Karnofsky Performance Scale score > 70 were also identified as independent predictors of RFS after resection of WHO Grade I meningioma. CONCLUSIONS In this patient cohort, a significant association was noted between extent of resection and rates of tumor recurrence. In the authors' experience the Simpson grading system maintains its relevance and prognostic value and can serve an important role for patient education. Even though complete tumor resection is the goal, surgery should be tailored to each patient according to the risks and surgical morbidity.

World Health Organization Grade I Convexity Meningiomas: Study on Outcomes, Complications and Recurrence Rates

The clinical significance of the Simpson grading system of extent of meningioma resection and its role as a predictor for recurrence of World Health Organization (WHO) grade I meningiomas have been questioned in the past, as microsurgery and knowledge of pathologic details have advanced. Clinical and radiologic information on 112 patients with WHO grade I convexity meningiomas who underwent surgery over the past 20 years was retrospectively reviewed. The recurrence rate in the grade 0-I resection group was 2.9%, whereas in the grade II-IV resection group, the recurrence rate was 31% (P= 0.0001). In Cox regression analysis, Simpson grade 0-I resection was revealed as a significant predictor of recurrence-free survival (P= 0.021). The hazard ratio for recurrence after II-IV resection was 10.98 times higher than grade 0-I. Like the Simpson grading of resection, a similar trend of recurrence (grade I, 1.6% vs. grade II-IV, 28%, P= 0.0001) was observed in the Shinshu grade of resection. In univariate analysis, female gender and use of neuronavigation were also identified as independent predictors of recurrence-free survival after resection of WHO grade I meningiomas. Six months after surgery, use of antiepileptic medication was less in grade 0-I compared with other grades. When histologic grade is fixed, the Simpson grading system is the prime predictor for recurrence of meningioma after resection. Grade 0-I resection is also beneficial in cutting off antiepileptic medication in patients with convexity meningiomas. Although complete tumor resection (grade 0-I) is the goal, the surgical approach should be tailored to each patient depending on the risks and surgical morbidity.

Treatment Strategy of Intracranial Hemangiopericytoma.

BackgroundRecent studies suggest aggressive management combining a grossly total resection (GTR) with adjuvant radiotherapy (RT) as a treatment of choice for intracranial hemangiopericytoma (HPC). However, in these papers, the definitions of complete or GTR are equivocal. In the present study, we reviewed the relevant cases from our experience focused on the clinical efficacy of surgical grading of resection, and analyzed the optimal treatment strategies as well.MethodsFrom January 1995 through December 2014, 17 patients treated for intracranial HPC were included in this study. We analyzed clinical presentation, radiologic appearance, pathologic diagnosis, extent of resection, and follow-up outcomes.ResultsA total of 26 operations were performed including 9 recurrent intracranial HPCs. Every tumor was single and had no evidence of metastasis. Most common area of tumor was parasagittal (8 patients, 47.1%), which is adjoined to superior sagittal sinus. For the initial operation, GTR was performed in 16 cases (61.5%), partial resection (PR) in 8 cases (30.8%), and an endoscopic biopsy in 2 patients (7.7%). In Simpson grading system, grade 1 was done in 2 patients (7.7%), grade 2 in 11 patients (42.3%) and grade 3 in 3 patients (11.5%). Postoperative RT was delivered in 16 patients (94.1%) regardless of the extent of resection. The median 57.57 Gy (range, 50-60 Gy) was delivered in median 33 fractions (range, 30-40). The extent of resection (conventional classification and Simpson grading system) and adjuvant RT were significantly associated with recurrence-free survival.ConclusionSurgical resection of intracranial HPC, in an attempt to reach Simpson grade 1 removal, is necessary for better outcome. Adjuvant RT should be done as recommended before, to prevent recurrence, regardless of surgical resection and pathological diagnosis.

MS-06 * DEFINING THE OPTIMAL FOLLOW-UP SCHEDULE FOLLOWING SURGICAL RESECTION OF GRADE I MENINGIOMA

BACKROUND: Extent resection is the standard practice for predicting recurrence/progression in meningioma. A number of studies have questioned the use of the Simpson grading system in modern neurosurgery. The aim remains to obtain an accurate prediction of recurrence risk so that a safe follow up/imaging schedule can be implemented. METHODS: Retrospective study of all resected WHO grade 1 meningioma at the Walton Centre NHS Foundation Trust from 2002 - 2007. Anatomical location, Simpson clearance, outpatient and imaging follow up and recurrence/progression time and actions were recorded. Descriptive statistics and Kaplan-Meier curves were plotted to calculate recurrence/progression free time by anatomic location, Simpson grading, gross total resection (GTR = Simpson 1-3) and subtotal resection (STR = Simpson 4-5). RESULTS: 145 records were included (74.5% females). Tumour location was: parasagittal/ parafalcine 24.1%; convexity 22.8%;and skull base 53.1%. Simpson resection was grade 1: 21.4%; grade 2: 42.8%; and grade 4: 35.2%. GTR was 64.1% and STR 35.9%. Median follow up was 60 months. Median number of follow-up MRI and clinic appointments was 5. Recurrence/progression occurred in 11.7%, 3 convexity with median reccurence/ progression time 68.3 months, 2 parasagittal/ parafalcine, median time of 24 months and 12 skull base with a median time of 53.3 months. PFS was 96.8% for Simpson 1, 100% for Simpson 2 and 82.4% for Simpson 4. PFS for GTR was 98.9% and for STR was 82.7% (p = 0.005). CONCLUSIONS: Extent of resection (GTR or STR) determines risk of recurrence. For convexity and parasagittal meningioma with GTR, follow-up MRI is sufficient for years 1, 2 and 5. Skull base tumours and STR in any location should have annual MRI.

Long-term survival analysis of atypical meningiomas: survival rates, prognostic factors, operative and radiotherapy treatment.

The rarity and the inconsistent criteria for defining atypical meningioma prior to the WHO 2007 classification made its management and prognostic factors poorly understood. Only few articles have addressed the survival rates of WHO-classified atypical meningiomas. The small number or the disproportionate representation of irradiated patients was a weakness for these articles. This study evaluated whether the extent of surgery and receiving adjuvant radiotherapy after an initial operation along with other patient characteristics influenced the recurrence and survival rates of atypical meningiomas. The clinical and surgical notes of the 79 patients with grade II atypical meningioma treated at our center over 13 years were retrospectively evaluated. The histology grading was consistent with WHO 2007 classification. The Simpson grading system was used to assess the extent of surgical resection. Kaplan Meier analysis, Cox multivariate regression analysis, and the Log-rank test were conducted using STATA® statistical package. The average age at the time of initial operation was 58 years, and 54 % were males. The mean follow-up period was 50 months. In Cox multivariate analysis, only Simpson grading was predictive of recurrence (hazard ratio = 2.22 / 1 increase in Simpson grade. p = 0.003). Simpson grade I patients had a relapse-free survival rate of 97 and 74 % at one and five years, respectively, compared with 88 and 32 % in the subtotal resection group (Simpson grades II to IV). There was no statistically significant correlation between recurrence and subjecting patients to postoperative radiotherapy. Apart from Simpson grade I patients, there was a general trend for worse outcome in irradiated patients. The most important prognostic factor in determining recurrence was Simpson grading. There was no statistically significant impact of adjuvant radiotherapy on the recurrence of atypical meningiomas. Meta-analysis for the existing literature is needed.

Surgical management of midline anterior skull base meningiomas: experience of 30 cases.

Midline anterior skull base meningiomas include olfactory groove meningiomas (OGMs), Tuberculum Sellae meningiomas (TSMs), and planum sphenoidale meningiomas (PSMs). The main surgical challenge in treating these lesions is to excise the tumor totally without causing mortality or morbidity. Studying the clinical patterns and the surgical outcomes of these lesions. Thirty cases of midline anterior skull base lesions were included in our study. Patients were operated upon by four routes: (i) unilateral subfrontal, (ii) bilateral subfrontal, (iii) frontotemporal approach, and (iv) bifrontal basal interhemispheric. Extent of resection was classified according to the Simpson grading system. The functional outcome of the patients was assessed by comparing the preoperative and the postoperative neurological examination, as well as the Karnofsky performance scale. We had 14 OGMs (46.7%), 9 TSMs (30%), and 7 PSMs (23.3%). The most commonly utilized approach was the subfrontal approach (unilateral or bilateral) in 80% of the cases, followed by the pterional approach in 16.6% of the cases. Total removal was achieved in 86.7% of the cases; subtotal excision was achieved in 13.3% of the cases. 41.2% of our cases showed postoperative clinical improvement. We had two mortalities in our study, representing 6.7%. We did not detect any tumor recurrences in our follow up. The median preoperative Karnofsky scale was 85, while the median postoperative Karnofsky scale was 90. Midline anterior skull base lesions are becoming amenable for total surgical excision with minimal morbidities and mortalities. Most preferred surgical routes are the subfrontal and the pterional approaches.